Multiple exception-IntegrityError

Using Django Forms & APIs
1

I want to use two different exception, but IntegrityError part is not working. Any idea? Thanks in advance.

new_sample = Samples()
    try:
       if(Samples.objects.get(p_id_s=listItem[0])):
            Samples.objects.filter(p_id_s=listItem[0]).update(**new_item_details)
       except Samples.DoesNotExist:
            new_sample.__dict__.update(new_item_details)
            new_sample.save()
       except IntegrityError:
            messages.error(request, "Already have that id!")
            return HttpResponseRedirect("/")
2

I don’t see any situation where that error can be generated. What condition do you think can occur that would cause that exception to be thrown?